"The Dying Gaul" has the best kind of story in that it unfolds as a series of surprises, and yet every step, twist and turn seems inevitable in retrospect. Just in terms of plot, it's a meticulous piece of construction, with key information gracefully planted and nothing extraneous. On mechanics alone, it would qualify as satisfying entertainment. Yet "The Dying Gaul" is hardly a mere mechanical construction.

Over the course of the film, the three central characters go through a series of transformations, deepening and hardening, shifting gears and maneuvering, revealing sides of themselves that they didn't know about and that surprise us. Written by Craig Lucas, based on his play, it was also directed by Lucas, his first feature film. Lucas' insight into the subtleties of interaction -- and the churning depths that those subtleties suggest -- is of a whole other order than that of most film directors. In this psychological thriller, the psychological isn't neglected; it's intrinsic.

The film travels a lot of emotional ground in 105 minutes. In its first seconds, it could even be mistaken for a Hollywood satire. Campbell Scott plays Jeffrey, a successful producer, and he wants to buy a screenplay from Robert (Peter Sarsgaard), a struggling writer. The screenplay is all about the death of Robert's lover from AIDS, but Jeffrey wants a fundamental change: He doesn't want the protagonist to be a gay man, but a straight woman.

The clue that Lucas is not interested in satire is that Jeffrey hardly comes across as a boor. His arguments in favor of the change make sense. He's persuasive. In addition, he has a beautiful home -- not only huge and expensive, but tasteful, with a stunning view -- and the intelligent good sense of his wife, Elaine (Patricia Clarkson), speaks well of him. Thus, as Lucas sets it up, we have three people, more or less well-meaning and more or less honest. Sure, they're self-interested and their relationships are all tied up with commerce, but that's life. In that nice California way, they become friendly very quickly and feel sure they know the others inside out, even as they hold on to their own secrets.

The immediate intimacy of the characters has both the ring of truth and a sadness about it. The sadness is that it's not at all phony, but it's not real, either. What feels like closeness, a true meeting of minds, is in fact just coziness, an expression of the desire to connect, not a real connection. Robert and Elaine, talking at the end of a movie screening, have their heads almost touching, and they look like best friends. They even think they're becoming best friends. What they're becoming is, in fact, something a lot more complicated.

Lucas creates an intense set of circumstances in which each character desperately needs something from the other two characters and has a specific reason to fear the other two characters, as well. It's best to leave the details vague. Suffice it to say that the situations and emotions that Lucas puts into place reach an intensity worthy of the film's title. It's taken from the haunting Roman sculpture, housed in Rome's Capitoline Museum, of a naked Gallic soldier, dying of wounds on the battlefield.

Lucas builds in effective wordless interludes that never once suggest a director trying to "open up" the play but rather an artist using the opportunities of film to communicate more meaning. In an early sequence, Elaine reads the original version of Robert's screenplay (called "The Dying Gaul") and is moved to tears at precisely the moment that Robert, in his apartment, is preparing to start chopping up his work at the behest of her husband. The performances of Sarsgaard, Clarkson and Scott are outstanding. One thinks of them here as an ensemble -- vulnerable, defensive and monstrous.

Much of the movie takes place with Robert and Elaine online, speaking to each other in chat rooms, through aliases. Onstage, these scenes would inevitably have to be static, but through voiceovers, flashbacks and graceful camera movement, Lucas makes these interludes dynamic.

Latest from the SFGATE homepage:

Click below for the top news from around the Bay Area and beyond. Sign up for our newsletters to be the first to learn about breaking news and more. Go to 'Sign In' and 'Manage Profile' at the top of the page.